FOXBORO — From the very first series on Friday night at Gillette Stadium, coach Bill Belichick was treated to a mixture of positive and stomach-churning plays. Good thing it’s only August.

FOXBORO — From the very first series on Friday night at Gillette Stadium, coach Bill Belichick was treated to a mixture of positive and stomach-churning plays. Good thing it’s only August.

The Patriots enjoyed their share of highlights but flipped in plenty of mistakes as well in a 42-35, back-and-forth victory over the Philadelphia Eagles.

This one featured a bit of everything. There were interceptions run back for touchdowns, blocked punts, acrobatic receptions for TDs, missed field goals and enough penalty flags to make the Bristol Fourth of July parade look staid.

“It’s always good to put 42 points on the board,” Belichick said. “We’ll look at everything and see what we did good and what we need to work on.”

The first series typified New England’s evening. The Pats won the toss and elected to take the ball (a clear sign we weren’t playing for real) and Tom Brady, in his preseason debut, quickly moved the ball. After passes to Danny Amendola and Kenbrell Thompkins, Brady looked up the sideline for Steve Maneri, a tight end who is used to blocking a lot more than running pass routes.

Maneri looked back for the ball a few seconds late, and by then the Eagles’ Cary Williams had jumped the route and grabbed an interception. Williams raced up the sideline, danced around Brady, who made a good attempt at a tackle and then kept motoring for a 77-yard touchdown.

“It was just a miscommunication. It happens,” Brady said of the interception. “I’m glad it happened in the preseason.”

The Pats took the ball back and again went to work nicely. Most of their gains came on the ground and, interestingly, Belichick went without a tight end at times, instead opting to send Nate Solder onto the field as an extra eligible receiver. Brady capped off a nine-play, 74-yard drive with a 15-yard scoring pass to Thompkins.

“KT made a great catch,” said Brady. “I’ve got so much confidence in him and what he’s capable of.”

With 5:09 left in the opening quarter, the Eagles finally got a chance to run a play from the line of scrimmage. It didn’t go so well. Nick Foles hit Ifeanyi Momah in the flat for an 8-yard gain, but when Malcolm Butler and Dont’a Hightower converged on the ball, Momah coughed it up for a fumble. Tommy Kelly recovered and New England’s offense was back in business at Philly’s 28.

This time Brady (8 of 10, 81 yards, TD, INT) stayed on the sidelines in favor of rookie Jimmy Garoppolo. He quickly went to work, hitting James Develin in the flat for 12 yards and then hooking up with the former Brown University defensive end for a 15-yard touchdown pass. Stephen Gostkowski’s kick gave the Patriots a 14-7 lead.

Garoppolo added a second TD pass the next time the Patriots got the ball, this time a third down score for four yards to Brandon LaFell that made it 21-7.

By that point, the Eagles’ offense had run just seven plays from scrimmage. But Chip Kelly’s attack, led by Foles and running back LeSean McCoy, finally made its mark. By then, many of New England’s defensive starters were out of the game. The Eagles received a big assist from the Pats’ special-teams unit when Ryan Allen had a punt blocked midway through the second quarter. The Eagles took over at the New England 31, and four shotgun passes later Foles hit Zach Ertz with a six-yard TD pass.

Garoppolo couldn’t get anything going on the next series, and Mark Sanchez, the Eagles’ backup QB, came on with 1:48 to play. He went to work with great precision, connecting on all five of his passes to drive Philadelphia 61 yards in five plays. The scoring catch was a beauty as Momah had the ball flip through his hands but settle into the waiting arms of Arrelious Benn.

Despite the 21-21 score, the Pats appeared to dominate the opening half. They outgained the Eagles, 246-155, and converted on 7-of-10 third down plays. But the Brady interception and Allen blocked punt stood out as key miscues.

Ryan Mallett (7-of-11, 92 yards, TD) ran the offense for New England the entire second half and put 21 points on the board in the third quarter. Mallett hit Brian Tyms for a 17-yard touchdown late in the third for a 42-28 Patriots lead, but the Eagles didn’t go away.

Philadelphia’s third-string QB, Matt Barkley, ended the third quarter with a 27-yard touchdown pass to Henry Josey. With just inside five minutes to play, the Eagles drove to the New England 2-yard line. Barkley handed off to Damaris Johnson on four straight plays but the Pats held the line, protected their lead and secured the victory.

There were a whopping 29 penalties called in the game and 21 were accepted. The Patriots had 11 of the penalties and the players say they’ll need to adjust to several new rules over the next two weeks.

“It’s a new rule in 2014 that they’re emphasizing with illegal contact down the field so we have to do the best we can,” said Darrelle Revis. “I don’t know how many penalties it was. It was a lot from just watching the game and going through it. At the same time, the refs are going to call what they see.”